Gerolsteiner Brunnen GmbH & Co. KG (Gerolsteiner) is a leading German mineral water firm with its seat in Gerolstein in the Eifel mountains. It is well-known for its Gerolsteiner Sprudel brand, a bottled, naturally carbonated mineral water. This water, in addition to hydrogen and oxygen (H2O) and carbon (in the carbon dioxide (CO2) carbonation), contains at least the following chemical elements in amounts of 100 or more micrograms per liter: bromine, calcium, chlorine, fluorine, lithium, magnesium, manganese, nitrogen, potassium, silicon, sodium, strontium, and sulfur. The strontium is naturally occurring, not the radioactive strontium-90. Gerolsteiner was also the chief sponsor of a cycling team, Team Gerolsteiner.